If a dog hurts someone because its owner didn’t take reasonable care to control the animal, the owner could be legally responsible for the injury.

Americans love their dogs. But dogs—even normally gentle or old dogs—hurt people all the time, even by accident. When that happens, the victims generally aren’t shy about suing to try to get compensation for their injuries. In some of those lawsuits, the victims will argue that the dog owners are liable for the injuries because they were negligent (legalese for careless) in handling their pets.

What Does It Take to Prove Negligence?

In order to win a lawsuit based on negligence, the injured person must prove that:

the owner had a duty to take reasonable care to control the dog's behavior

In addition to all of these “elements,” courts may look at another factor when deciding whether someone was negligent: whether the injury was “reasonably foreseeable,” meaning the dog owner should have been able to expect that it would happen under the circumstances.

It’s not all that common for dog-bite victims to sue based only on negligence. Most states have “strict liability” laws that make owners automatically liable for most dog-bite injuries; there’s no need to prove the owner was negligent or knew the dog was dangerous. Victims usually turn to a negligence claim in states without strict liability dog-bite laws or in circumstances where the law doesn’t apply—for instance, if it only covers bite injuries, but an injury happened when a dog jumped on someone. And in states that use the “one-bite rule”—which makes dog owners liable for injuries only if they knew or should’ve known their animals could be dangerous—victims who can’t prove that knowledge may sue for negligence. (However, the dog’s history could still play a role in a negligence suit; more on that below.)

Still, it can be difficult to prove all the elements of negligence. The outcome of any case depends on the particular circumstances, as well as how other courts in the state have interpreted the law.

When There’s No Duty of Care

As a general rule, dog owners have a duty to use reasonable care in order to prevent their animals from injuring others in predictable ways. But that duty doesn’t necessarily extend to everyone, such as a burglar who has broken into a dog owner’s house. And in some circumstances, it may not even apply to innocent passersby. In a Colorado case, two pit bulls barked and lunged at a passing eight-year-old boy from behind a chain link fence that held them in their yard. The dogs didn't escape from the yard or touch the boy. But he got scared and ran into the street, where a van hit him. The boy's parents sued the dogs’ owner, claiming that he was negligent by not preventing the pit bulls from frightening people walking in front of his house. But the Colorado Supreme Court found that the owner didn’t owe a duty of care to the passing child, so there wasn't any negligence. (N.M. by and through Lopez v. Trujillo, (397 P.3d 370 (Colo. 2017).)

What’s Reasonable Care?

A lot of factors can affect whether a court will find that a dog owner acted reasonably, including:

Chains, fences, and warning signs. Courts are likely to find that an owner has taken reasonable precautions if the dog is confined in the owner’s property with a “Beware of Dog” sign (see, for example, Alfano v. Stutsman, 471 N.E.2d 1143 (Ind. Ct. App. 1984)). But a warning may not always be necessary. A court found that a dog’s owners weren’t liable for their house guest’s injuries from falling down stairs after she was frightened when the hosts’ dog growled from another room. The owners had taken reasonable precautions by keeping the dog behind a locked gate, and they didn’t need to warn the guest about its presence. (Partipilo v. DiMaria, 570 N.E.2d 683 (Ill. Ct. App. 1991)).

The dog’s history. In most states, owners may be found negligent even if their dogs didn’t have a history of dangerous or mischievous behavior. Still, a dog’s past behavior will often affect the question of much control is reasonable. For instance, when a dog had a history of getting upset and growling when people leaned toward it, the owner should’ve warned a dog sitter or restrained the dog (Mann v. Regan, 948 A.2d 1075 (Conn. Ct. App. 2008)). And when dogs have a history of chasing passersby or vehicles in a menacing way, their owners may be negligent by allowing the animals to run loose. That means they could be liable when cyclists swerve to avoid the dogs and fall. (See Laylon v. Shaver, 187 A.D.2d 983 (N.Y. App. Div. 1992) and Henkel v. Jordan, 644 P.2d 1348 (Kan. Ct. App. 1982).) In contrast, a court found that the owner of a dog with no vicious tendencies didn’t have to take any special precautions beyond keeping the animal behind a fence. That meant the owner wasn’t negligent by leaving out some cinder blocks that the dog used to reach the top of the fence and bite the finger of someone walking by. (Russell v. Rivera, 780 N.Y.S.2d 699 (N.Y. App. Div. 2004).)

The dog’s breed. Some courts may presume that a dog owner knows the animal can be dangerous because of its breed, which means that the failure to take special precautions could amount to negligence (see Poznanski v. Horvath, 788 N.E.2d 1255 (Ind. 2003)).

The owner’s violation of the law. If a dog injures someone because its owner was violating the law, the court may either find that the owner was negligent as a matter of law (in which case the injured person only has to prove there was a legal violation) or consider the owner’s actions as evidence of negligence. The most common example is when an owner violates a local leash law by letting the dog run loose, and the dog bites someone or causes an accident. (For example, see Phiel v. Boston, 586 S.E. 718 (Ga. App. 2003) and Delfino v. Sloan, 20 Cal. App. 4th 1429 (1993).) Courts will also generally assume that dog owners were negligent if they didn’t meet the legal requirements under a state’s dangerous-dog law.

Tips for Owners: Good Practice to Prevent Dog Bites

If you own a dog, preventing it from hurting someone is obviously the best way to avoid liability for an injury. Certain simple steps help, like training and socializing your dog, never letting it run loose, paying special attention when children are around, keeping the animal out of the path of strangers (like mail carriers and others who will routinely enter your yard to come to the front door), and posting a clear “Beware of Dog” sign if you have any reason to believe that it might injure someone coming onto your property. Even if the dog hurts someone despite these measures, your preventative actions could help show that you weren’t negligent.

Did Negligence Cause the Injury?

If a dog bites someone because of its owner’s carelessness, it’s pretty clear that the negligence caused the injuries from the bite. But the question of “proximate cause” is more complicated when the dog hasn’t actually bitten or even touched the injured person. The most common example is when someone gets hurt while running from or trying to avoid a scary dog. In many cases involving dogs chasing cyclists who then fell (discussed above), courts have found that the negligent owners were liable. But the result could be different if the frightened person acts erratically—like suddenly stepping into the street and getting hit by a car; in that case, the court may decide that the car caused the injury, not the dog (see Sink v. Moore, 148 S.E.2d 265 (1966).

Where Negligence Doesn’t Matter

Not all states allow someone injured by a dog to sue on a negligence claim. For instance, as a result of court decisions in New York since at least 2009, pet owners in that state won’t be liable for injuries unless they knew or should’ve known than their animals could be dangerous (Petrone v. Fernandez, 910 N.E.2d 993 (N.Y. Ct. App. 2009).) And in Alabama, a dog owner isn’t liable for injury caused by the animal unless the owner knew about its dangerous or mischievous tendencies (Williams v. Hill, 658 So.2d 381 (Ala. 1995).)

Speaking With an Attorney

If you’ve been hurt by a dog, or you’re being sued by someone who blames you and your dog for an injury, you should consider speaking with a personal injury attorney. The legal rules about proving negligence in a dog-bite case can be complicated and can vary significantly from state to state. Whether you’re the injured person or the dog owner, a lawyer experienced in this area can explain how the law applies to your situation, and can help protect your rights.